This invention is related to input/output devices and more particularly to electrical terminals that are used to interconnect adjacent modules in an input/output device.
It is well known in the art to use a plurality of electronic input/output modules that fit together in a stacked arrangement and are electrically connected together. It is also known that the modules may be mounted to a U-shaped metal rail that supports the device and provides electrical connection to ground.
U.S. Pat. No. 5,775,955 discloses one such arrangement in which each module has plug-compatible male and female connectors that are electrically engaged by sliding a loose module along a rail and into engagement with modules that are fixed to the rail. To repair or replace a selected module in the stacked arrangement, it is necessary to slide and remove all the modules to one side of the selected module from the rail before the selected module can be removed, repaired or replaced. The whole process is then repeated to remount all the modules. This process can cause excessive wear on components that may engage the rail as well as take time. It is desirable, therefore, to have a module that can be removed and remounted to a rail without disturbing the other modules on the rail.
U.S. Pat. No. 4,956,747 discloses modules having base portions with spring contacts extending from one side to the other of each base portion. The forces generated by the spring contacts as they are compressed by engagement with terminals in adjacent modules act in a direction parallel to the rail and in a direction to push the modules apart, thus requiring the use of interlocking housing portions or the like to assure the modules remain together. Additionally, as more modules are added, the amount of force builds up. It is desirable, therefore, to have terminals that interconnect adjacent modules in which the forces are xe2x80x9cself-containedxe2x80x9d, that is do not act to push the modules apart and do not build up as the number of modules on the rail are increased.
U.S. Pat. No. 5,719,241 discloses modules that can be mounted to the rail in a direction orthogonal to the rail. The modules use flat bar-like power bridging members and terminals having resilient spring arms for interconnecting adjacent modules.
The present invention is directed to an electrical terminal usable in input/output modules mounted to rails that overcomes problems associated with the prior art. The terminal is suitable for use as both a power and/or a data terminal in such a module. For purposes of illustration, the terminal will be shown as a power terminal in an input/output module. It is to be understood that the terminal is not limited to use in such a module.
The electrical terminal for interconnecting electronic modules in a stacked arrangement includes a U-shaped body having first, second and third connecting portions. The body has a base and opposed legs extending to free ends adapted to be electrically connected to circuits of a circuit board and defining the first connecting portion. A blade contact extends outwardly from one of the legs intermediate the base and free end and in a direction substantially perpendicular to the first connecting portion. The blade contact defines the second connecting portion. A receptacle contact extends outwardly from at least one of the legs intermediate the base and free end and in a direction substantially perpendicular to the first connecting portion and opposite to that of the blade contact. The receptacle contact defines the third connecting portion. Upon disposing the terminal in a terminal receiving passageway of a module with the first connecting portion electrically engaged to a circuit board therein and the second and third connecting portions being proximate openings in the passageway on opposite sides of the module, the second and third connecting sections are available for being mated with complementary connecting portions of adjacent modules in a stacked arrangement.
In the embodiment shown, the receptacle contact is a pair of spring arms, with one arm extending from each of the legs of the U-shaped body. The leading end of the blade contact is offset from the leg such that the blade contact is in alignment with the space between the spring arms such that the terminal is hermaphroditic.
The invention is also directed to an electronic module having at least one of the above terminals disposed therein.
An embodiment of the invention will now be described by way of example with reference to the accompanying drawings.